Police have clashed with protesters in the Azerbaijani capital, Baku, after an antigovernment rally.

The police intervention came after hundreds of demonstrators held a rally on September 17 protesting an upcoming referendum that would give Azerbaijani President Ilham Aliyev greater powers and a longer term in office.

Several journalists were also detained by police during the clashes, including at least two freelancers working for RFE/RL's Azerbaijani Service.

One RFE/RL journalist was taken from the scene of the protest in a bus with some 30 detainees.

There were no immediate reports of injuries.

The protest, which was sanctioned by the government, was organized by the National Council of Democratic Forces, an umbrella organization uniting part of Azerbaijan's opposition forces.

WATCH: Footage Of The Baku Protest (natural sound)

Demonstrators oppose the holding of a September 26 referendum in the tightly controlled South Caucasus country that is expected to strengthen the authority of Aliyev, extend the length of presidential terms, and drop the minimum age for future presidential candidates.

Some slogans at the rally included "No to monarchy, end to robbery!" and "Where is the $140 billion oil money?"

Activists have warned that Azerbaijan’s government has stepped up the repression of journalists, civil society activists, and human rights workers ahead of the referendum, and urged the West to do more to confront Baku.

The oil-rich South Caucasus nation has faced growing social and economic problems stemming from falling world oil prices in recent years.

In an environment of total government control over national television and radio channels, Radio Azadliq has a firm reputation as the only source of unbiased information and the most professional media outlet in Azerbaijan.